1. Field of the Invention
The present invention relates to a backlight module for a liquid crystal display device and, more particularly, to a backlight module, of which the lamp can be disassembled and replaced with ease.
2. Description of Related Art
According to the location of light sources, the backlight module of the liquid crystal display device is classified as a side-light or edge-light type and a direct-light (bottom light) type. The side-light or edge-light type backlight module requires a light guide plate and is commonly applied to notebook computers. As for the direct-light type backlight module, it does not need a light guide plate and its lamps are mounted directly at the bottom of the backlight module. In the direct-light type backlight module, the light emitted from the lamps becomes uniform after passing through the diffusing plate and thereafter enters the liquid crystal panel. In recent years, manufacturers have increasingly paid attention to the liquid crystal display devices of a large size, such as the liquid crystal television. Generally, the liquid crystal television uses the direct-light type backlight module. In order to meet the requirement of high brightness, the quantity of lamps used in a direct-light type backlight module can be up to sixteen or more. Although the lifetime of a lamp can be more than 10,000 hours, it is still hard to prevent the non-uniform brightness caused by deterioration of lamps. Traditionally, when the lamp mounted in the direct-light type backlight module has deteriorated, the glass panel, the diffusing plate, the metal frame, the plastic frame, and so on have to be disassembled and then the deteriorated lamp can be changed. Therefore, the change of lamp is time-consuming, and can only be carried out by a professional. Furthermore, the maintenance cost of such a TV is high and the general consumers have to put up with the drawbacks aforementioned. Also, the popularization of liquid crystal television is hindered by such limitations.
Japanese Patent No. 4-366815 disclosed a reflective plate that was divided into a plurality of parts in order to facilitate the replacement of the lamps. However, it is mainly focused on the liquid crystal display device of small size or low brightness, which has few lamps. As for the liquid crystal display device of large size or high brightness, it usually has more than ten lamps. If the reflective plate is divided into so many reflective parts, not only will the assembling become complex, but also the rigidity of the reflective plate will be lowered. Consequently, the reflective plate will be easily loosened and broken, which will further lead to increases in both failure rate of products and manufacturing cost. Subject matters disclosed in U.S. Pat. Nos. 5,815,227 and 5,537,296 are suitable for the conventional side-light type backlight module. Moreover, the technique of U.S. Pat. No. 5,537,296 involves the mounting of a plurality of backlight modules, which is excessively complex in assembly and difficult to be implemented in direct-light type backlight module. U.S. Publication Patent No. 20030086255 disclosed a direct-type back light device. Although the subject matter disclosed in the U.S. Patent Publication No. 20030086255 can be applied to the liquid crystal display device that has plural lamps or large size, it is necessary to disassemble the external supports or the lamp holders when the lamp is changed. So it is time-consuming and easy to damage the lamps.
Therefore, it is desirable to provide a backlight module for a liquid crystal display device to mitigate and/or obviate the aforementioned problems.